By the title I mean, the PDF will update if I build the code while SumatraPDF is already open. But if SumatraPDF is closed, then when I build the code, it says the texification succeeded, however the PDF will not open.

How do I get it so that when I build the code it will also open SumatraPDF (When it's closed)?

Well when I double click on the PDF, it would open up Sublime Text 2, so it is on the inverse command line.And in the viewPDF.py file in the Inverse viewer CMD, I have it set to "C:\Program Files (x86)\SumatraPDF\SumatraPDF.exe"

Backtick is the little backward single quote. On a US keyboard, it's under the tilde. You can also go to the View menu and select "Show Console." That will show you the debugging console for Sublime Text, and there may be something useful there.